Tank Parameters

[CWalters]

I would say you are well within the testing error we all experience. You could probably test it 50 times and get 50 different results. As long as they are all within about 5%, I would say you are okay.

my experience is I use a 75 gallon storage tank and auto change two gallons a day. It takes 30 days before I put in new salt water in the storage tank. That’s enough time for precipitation and the alkalinity starts dropping in the stored water. If you are mixing it and immediately doing your water change, 8.5 Alk should be good. If you feel it’s not, you might consider a salt (like reef crystal) that has a much higher Alkalinity.

Interesting... Yea I do store about 44 gallons of RODI water and a few gallons of mixed for emergencies. Could be part of the probelm.

 

[CWalters]

You do know you can increase alkalinity with sodium bicarbonate? Your new salt looks ok, as does your testing. Test your tank again, just in case you’ve done something daft, before taking action.

I know about additives I can add. I just wanted to know if there was a problem I could fix before I start dumping stuff into the tank.